Potentiometer-accelerometer apparatus



y 1959 M. E. BOURNS ETAL 2,836,675

POTENTIOMETER-ACCELEROMETER APPARATUS 2 Sheets-Sheet 2 Filed March 30,1955 United States Patent POTENTIOMETER-ACCELEROMETER APPARATUS MarlanE. Rooms and Marvin E. Harrison, Riverside, and Alfred W. Stewart,Yncaipa, Calif.; said Harrison and said Stewart assignors to BournsLaboratories, Inc.

Application March 30, 1955, Serial No. 498,026

7 Claims. (Cl. 201-48) The present invention relates primarily to newand improved accelerometers, although certain features of this inventionare applicable to other related devices, such as, for example,potentiometers.

Those familiar with present day electrical components will realize thatthe term potentiometer is employed to designate a type of a variableresistor including a resistance element having end terminals designed tobe connected to a voltage source and including a movable contact whichmay be located at any desired point along this resistance element so asto obtain a voltage dividing action. If desired those devices termedaccelerometers can be considered to be a type of potentiometer sincethey contain the essential elements of a potentiometer, and, inaddition, means intended to be moved in response to acceleration so asto shift the position of a movable contact as previously indicated withrespect to a resistance element.

Potentiometers and accelerometers are widely employed at the presenttime in various guided missiles and related machines. As research onthis type of equipment has progressed there has been a substantiallyconstant demand for new and improved electronic instruments of the typeto which this invention relates. A number of qualities are desired insuch new instruments: they must be less subject to error than thepreceding units; they must be accurate; they must be light in weight;they must be comparatively insensitive to damaging influences; and theypreferably must be comparatively inexpensive.

A basic objective of this invention is to provide accelerometers which,when judged by the aforegoing criteria, constitute an improvement overthe prior units employed for the same purpose. A broader object is toteach the construction of various new and improved means which are, itis thought, primarily useful in accelerometers, but which are capable ofadvantageous application in various other related devices. Such meanswill be described in detail in the subsequent discussion. Those skilledin the art will recognize still further objects of this invention fromthe remainder of this specification including the appended claims andthe accompanying drawings in which:

Fig. l is a front or top view of an accelerometer of the invention;

Fig. 2 is a cross-sectional view taken at line 2-2 of Fig. 1;

Fig. 3 is a cross-sectional view taken at line 3-3 of Fig. 2;

Fig. 4 is a detail view showing the construction of a spring employed inthe accelerometer shown in Figs. 1, 2, and 3 of the drawings;

Fig. 5 is a detail view showing the construction of part of theaccelerometer illustrated in Figs. 1, 2, and 3 of the drawings;

Fig. 6 is a view similar to Fig. 2 of a modified accelerometer of theinvention;

Fig. 7 is a detail view resembling part of Fig. 2 of a second modifiedaccelerometer of the invention;

Fig. 8 is a view similar to Fig. 3 of a third modified accelerometer ofthe invention;

Fig. 9 is a detail view showing the construction of bimetallic stripsemployed with the invention; and

Fig. 10 is a detail view similar to Fig. 6 showing the construction ofanother modified accelerometer of the invention.

In all figures of the drawings like numbers are used to designate likeparts wherever convenient for purposes of illustration and explanation.It is to be understood that the relative proportions of the variousparts shown in the drawings have been changed from the actualproportional sizes of these parts in many cases in order to facilitatethe illustration of the invention.

In Figs. 1, 2, and 3 of the drawings an accelerometer 10 is shown whichincludes a can-like casing 12 having an open top which is sealed bymeans of a lid 14 attached to the casing 12 by the use of threads 16. Anappropriate conventional O-ring 18 of an elastomeric material is heldwithin a groove 20 so as to seal this casing 12.

Mounted upon the lid 14 through the use of screws 22 is a cage 24 whichfits within the casing 12. This cage is provided with an open upper end26 in which there is positioned a disc-like bellows mounting member 28formed of a non-conductive material. This bellows mounting member issecured to the cage 24 through the use of other screws 22. Further itincludes a central opening 30 within which there is held an adjustingnut 32. This nut is provided with threads 33 which engage correspondingthreads upon a projecting collar 34 forming a part of a bellows unit 36.The collar 34 is formed with an annular shoulder 38 which is intended toengage the bellows mounting member 28 as shown in Fig. 2 of thedrawings. However, if desired, this shoulder 38 may be spaced from themounting member 28 and the entire bellows unit 36 can be held inposition through the use of another screw 22 located within an elongatedpassage 40 formed within the bellows mounting member 28. When this isdone the position of the bellows unit 36 can be adjusted as desired.

The bellows unit 36 includes bellows 42 of any type of conventionalconstruction having a centrally formed opening 44 leading to anotheraligned opening 46 within a valve seat 48 secured to the bellows 42 andthe collar 34. The valve seat 48 is formed with a conical depression 50forming a part of the opening 46. Within the collar 34 there is locateda valve body 52 having a conical projection 54 which is adapted to fitwithin the conical depression 50 so as to regulate the fiow of air intoand out of the bellows 42 through the valve seat 48. Air passing throughthe opening 46 passes into the casing 12 through passages 56 formedwithin the valve body 52. The position of the valve body 52 with respectto the valve seat 48 is maintained by using other threads 57 securingthis valve body 52 to the collar 34. The valve body 52 may be locked inany given position through the use of a locking nut 58 which is alsoscrewed onto the threads 57.

The construction described in the aforegoing for mounting the bellows 42is considered to be quite important to the instant invention inasmuch asit constitutes a means whereby the flow of air into and out of thisbellows may be readily regulated so as to obtain any desired air dampingaction. The use of air damping in the accelerometer 10 is quiteadvantageous inasmuch as this type of damping is substantiallyindependent of temperature. When such damping means as liquids areemployed for the same purpose the viscosity of such liquids is changedat varying temperatures causing a corresponding alteration of aeaaers Sthe damping effect. Further, air clamping employed herein is a distinctimprovement over magnetic damping inasmuch as the parts required arerelatively simple to manufacture and handle, and do not occupy anyconsiderable space. Also with magnetic damping the parts employed areconsiderably heavier than the parts required for fluid damping. The termdamping as used herein is intended to cover those situations in whichmeans are employed to prevent undesired rapid movement of the variousoperative parts within the accelerometer 10.

This accelerometer includes a heavy disc or mass 60 which is secured tothe wall of the bellows 42 remote from the bellows mounting member 28.Attached to the disc 6! is a bushing 62 which is designed to carry a rod64 so that this rod is secured to the bellows unit 36 and projectsdownwardly therefrom. Screws 22 are employed for the obvious purpose ofholding the rod 64 within the bushing 62.

The extremity of the rod 64 remote from the bellows 42 is attached tothe central hub 66 of a spring 68 having radial arms 70. Theconstruction of this spring 68 is best shown in Fig. 4 of the drawings.secured to the disc-shaped bottom 72 of a non-conductive support member'74. This support member is secured to the cage 24 through the use ofscrews 22 so as to be generally parallel to the bellows mounting member28, and includes upstanding shaft supports 76 and a resistance support78. The bottom 72 is formed with a centrally located opening 86 throughwhich the rod 64 projects.

It is preferable to form either the entire spring 68 of a bi-metalsheet, although the resilient arms 70 alone may be formed of suchmaterial. When this is done the spring 68 can be constructed of suchmaterials as to compensate for any tendency of the bellows 36 to expandor contract when heated or cooled so as to bend with such temperaturevariation in order to hold the rod 64 in a given location during suchexpansion or contraction.

The shaft supports 76 each include an opening 80 having an internalflange 84 formed therein so that a metal shaft 86 may be mounted betweenthe supports 76 in such a manner as to be carried by rollers 88constituting roller bearings. These rollers 88 are held in position bymetal washers 90 and nuts 92 secured to the extremities of the shaft 86.

Attached to the shaft 86 so as to project therefrom is a generallychannel-shaped arm 94 formed of metal upon the end of which there islocated a conductive spring contact 96. If desired this contact 96 maybe formed of a single sheet of material including resilient fingers 97.If desired this contact 96 may be termed a first electrical meansinasmuch as it is designed to be moved along one surface of an arcuateresistance member 98 held within a correspondingly shaped slot 100formed within the resistance support 78. The contact 96 bears againstthe resistance element with light spring tension, owing to the inherentresiliency of the contact. The resistance member 98 may, if desired, betermed a second electrical means and may consist of any of a number ofgeneral types of prior art constructions. It is preferred, however, thatthis resistance member include a non-conductive base 102 around whichthere is located a coil 104- of wire having appreciable electricresistance.

During the operation of the accelerometer 16 as this accelerometer issubjected to accelerating forces the disc 66 will be caused to movewithin the casing 12. This in turn' causes air to either be forced intoor out of the bellows 42 during expansion or contraction thereof movingthe rod 64 along a line within the casing .12. This motion of the rod 64is transmitted to the shaft 86 through the use of linkage means forminga unique part of the present invention. This linkage means includes fourbimetallic strips 106 of generally bowed configura- The arms 70 are tionsecured together in pairs as is indicated in Figs. 2 and 3 of thedrawings so that the extremities of all of these bimetallic strips 106remote from the shaft 86 are attached to one another by means of a pinor shaft 108. All of the other extremities of the bimetallic strips 106are secured directly to. the shaft 86. The pin 108 is designed to slidewithin a slot 110 formed by other pins 112 projecting from the rod 64.

The bimetallic strips 106 are preferably formed as briefly indicated inFig. 9 of the drawings, and comprise layers 114 and 116 of differenttemperature coefficients of expansion. Thus, with this construction, asthe bimetallic strips 106 are heated they will bend causing the pin 108to be moved within the slot 110 away from the shaft 86. This varies thelength of the effective lever arm connecting the rod 64 to the shaft 86.By appropriate selection of the material of which the bimetallic strips106 are formed it is possible through this means to provide aconstruction in which the amount the contact 96 is moved along theresistance member 98 at different temperatures varies in accordance withthe temperature of the accelerometer 10. Thus, it is possible to formthe accelerometer It in such a manner as to compensate for expansion andcontraction of the various movable parts within this unit and for thechange in spring rate of the bellows 36 and of the spring 68 so that theelectrical signal obtained from it is independent of the temperature atwhich the unit is being operated by constructing the strips 196 of suchmaterial and of such length that the expansion characteristics of thesestrips compensate for the expansion or the contraction and change inspring rate of the parts within the accelerometer.

The structure shown in Figs. 2 and 3 of the drawings is considered to beparticularly advantageous in that the movement transmitted to the shaft86 from the rod 64 is conveyed through linkage means disposed uponopposite sides of the rod 64. Thus with this structure the forces uponboth sides of the rod 64 are substantially balanced. Further, thelinkage means employed is composed of sufficient separate elements sothat the effect of vibration is substantially controlled. There issubstantially no tendency with this structure for the strips 106 to bendduring the operation of the accelerometer 10.

In the accelerometer Ill the movement of the rod 64 is conveyed to theshaft 86 by the means previously described. It should be pointed outthat these means are located intermediate the ends of the rod 64 andthat this rod is supported at both of its ends by what may be termedspring means. The first of these spring means is the bellows 42; thesecond is, of course, the spring 68. The bellows 42 may be considered toact essentially as a spring because of the inherent resiliency of itswalls.

With this type of structure the rod is held in such a manner that thedesired movement of this rod is possible, but so that undesired movementof the rod, except along the intended line of travel, is effectivelyprevented, elimihating possible error resulting from such movement. Thisis considered to be a distinct advantage over the prior relatedconstructions. The use of two spring means as herein described can beapplied to other units such as, for example, absolute pressurepotentiometers with substantially the same results as herein obtained.

The lid 14 is provided with a generally centrally located opening 118 inwhich there is mounted a rotatable member 120 having a sloping surface122 which is designed to bear against the screw 22 attached to the rod64 when this rotatable member 120 is turned 180 from the position shownin Figs. 1 and 2 of the drawings. The member 120 is held with respect tothe lid 14 by means of a snap ring 124 fitting within a groove 126formed in this rotatable member 120. It is secured against movementtoward the casing 12 by means of what may be termed a screwhead 128which is normally forced against an O-ring 129 located'against a flange130 within the opening 118. The screwhead 128 is formed with arcuaterecesses 132 spaced 180 from each other around this head. The purpose ofthe recesses 132 is to provide a convenient means by which the rotatablemember 120 may be locked in either the position shown in Fig. 2 of thedrawings or in the 180 position previously described when a screw 133 issecured to the lid 14 so as to engage either of these recesses.

Thus, the screw 133 may be used to lock the rotatable member 120 withthe surface 122 bearing against the screw 22 attached to the rod 64 soas to prevent undesired movement of this rod and the other partsoperatively connected thereto during shipment of the accelerometer Thisfeature of the invention is considered to be quite important inpreventing undesired damage to the unit due to rough handling duringshipment. The surface 122 is normally of such dimension as to force therod 64, when in such a locked position, as far away from the lid 14 asthis rod will move.

In order to complete the accelerometer 10 it is necessary to providevarious means by which current may be supplied to the resistance member98 and to the contact 96. With the accelerometer 10 such means includeshaftlike terminals 134 which are mounted within the lid 14 so as toproject from both sides thereof. An essentially conventional dielectricresin grommet 136 surrounding these terminals may be employed to holdthem in position and to insulate them from the lid 14. Wires 138 securedto the terminals 134 inside of the casing 12 are normally passed throughan opening 140 within the support member 74 and then are connected toconventional terminal means 142 mounted upon the resistance support 78.

These terminal means are in turn attached to the extremities of theresistance member 98 on the surface thereof remote from the contact 96.One of the wires 138 is attached to one of the nuts 92 so as to beelectrically connected to the contact 96.

In Fig. 6 of the drawings a modified accelerometer 144 of the inventionis shown which differs from the accelerometer 10 in several importantfeatures. In this unit the valve means connected to the bellows 44 areomitted and replaced by a single passage 146 extending through a stud148 which is roughly the equivalent to the collar 34 previouslydescribed. Also in this unit the rod 64 is replaced by a large diameterrod 150 formed of a comparatively very heavy material such as, forexample, lead or various steel alloys. The extremity of the rod 150adjacent to the lid 14 is secured within a bushing 152 attached toanother bellows 154. This other bellows is secured to a projecting stud156 on the wall thereof remote from the rod 150. The stud 156 is in turnlocated within an opening 158 formed within another bellows mountingmember 160 which is fastened by means of screws 22 in the cage 24between the lid 14 and the support members 74. A screw 22 is preferablyemployed to secure the stud 156 within this bellows mounting member.

The stud 156 has formed therein an opening 162 leading from the interiorof the bellows 154 to adjacent to the rotatable member 120. The purposeof this opening 162 is to provide a passage through which a rod or shaft164 can project from the Wall of the bellows 154 adjacent to the rod 150out into the space between the mounting member 160 and the lid 14. Thuswith this construction the rod 164 moves within the opening 162 duringexpansion or contraction of the bellows 154. It preferably fits closelywithin the opening 162. Further the rod 164 is provided with a periferalgroove 166 serving the same purpose as the passage 146 previouslydescribed. That is, this groove 166 serves to convey air into and out ofthe bellows 154 so as to serve as a damping means.

With the construction shown in Fig. 6 the bellows employed may be lockedin a position for shipment by adjusting the position of the movablemember 120 substantially as previously described. When this is done the6 sloping surface 122 engages the adjacent extremity of the rod 164 inthe obvious manner holding both of the bellows so that undesiredmovement is prevented.

The accelerometer 144 also differs from the accelerometer 10 in anotherimportant regard. In this unit two bimetallic strips 168 and 170 areemployed instead of the four bimetallic strips 106 previously described.These strips 168 and 170 are of substantially the same shape as thestrips 106 and are secured together so that their adjacent ends aresecured to the shaft 86 and the pin 108. With this construction thebimetallic strips 168 and 170 are located on one side of the rod thisstructure is sufliciently stable as regards to vibration for mostpurposes.

Frequently it is desired to form either of the strips 168 or ofdifferent metals than the other of these strips in order that thetemperature characteristics of the two separate strips will differ fromone another. Thus, with this type of construction not only will theefiective distance between the pin 108 and the shaft 86 change atvarying temperatures but also the position of the pin 108 will change ina direction generally parallel to the axis of the rod 150.

Those skilled in the art will realize that this particular type ofconstruction illustrated in Fig. 6 for the two bimetallic strips 168 and170 is exceedingly advantageous in producing units having specialtemperature varying characteristics. That is to say units employing thisfeature can be manufactured so that an electrical value will change in adesired manner with respect to temperature variation. Obviously thebasic feature of employing two different bimetallic strips illustratedin Fig. 6 of the drawings can be adapted to a structure such as is shownin Fig. 2 of the drawings by making the two strips 106 shown in thisfigure adjacent to the lid 14 of different metals than the remaining twostrips. Although the use of bimetallic strips as herein described isconsidered to be particularly advantageous in accelerometers it isthought that it may also be applied to other related units in whichmotion is transmitted from one member to another member in order to varyan electrical value.

In Fig. 7 of the drawings a structure is shown in which a singlebimetallic strip 172 is used to connect a shaft 86 and a rod 64 of thetype shown in the initial figures of the drawings. A construction ofthis category can many times be advantageously employed to providetemperature compensation, and it operates in essentially the same manneras the temperature compensating construction previously described.Inasmuch as only a single bimetallic strip 172 is employed this stripmay, in many cases, be subjected to vibration effects which are notmaterial with the other constructions previously described. It isconsidered obvious that two curved bimetallic strips, such as the strip172 illustrated in Fig. 7, can be employed on opposite sides of the rod64, both of these strips being secured to the pin 112 and the shaft 86.

In Fig. 8 of the drawings a modified construction of the invention isshown which differs from the accelerometer 10 in that a single rod 174of a material having appreciable temperature coefiicient of expansion isused instead of the bimetallic strips 106. This rod 174 is secured tothe pin 108 in the obvious manner and is preferably passed through anopening 176 within the shaft 86 so as to extend within a sleeve 178projecting from the opening 176 on the side of the shaft 86 remote fromthe rod 64. The rod 174 and the sleeve 178 are attached to one anotherby suitable means 180, such as, for example, solder. The advantage ofthis particular sleeve type of construction shown is that acomparatively long length may be provided for the rod 174.

A structure is shown in Fig. 10 of the drawings which is essentially amodification of the accelerometer 144 shown in Fig. 6. With thisstructure, a passage 182 is provided within the rod 150 so as to connectthe interiors aseaere of the bellows. 154. and, 36.. Appropriateopenings 184 are provided within these two bellows for the obviouspurpose. With this structure the rod 150 is secured to the two bellows36- and 154 through the use of collars 186 which are welded or otherwisefastened to these bellows. The rod 150 is also attached to the collars186 by means of welds or other equivalent means known to the art.

With the structure indicated in Fig. the rod 164 does not have thegroove 166 previously described. Thus a substantially fluid-tightfitting is obtained between this rod 164- and the stud 156 so that thequantity of fiuid within the bellows 36, the bellows 154, and thepassage 182 remains constant regardless of position of this rod 164. Thefunction of the rod 164 is substantially as previously described. Ifdesired, it may be omitted with the corresponding omission of itsfunction. The rod 164 in the structure shown in Fig. 10 is attached tothe bellows 154 by means of a small spider Hi8, which is similar inshape to the spring 68 previously described, the spider I188 beingsecured to both the rod 164 and the bellows 154 by means of welds or thelike.

It is possible with this structure described in the aforegoing to fillthe two bellows 36 and 154 with virtually any desired fluid so that thefluid is contained within these two bellows and with the passage 182 atall times. Thus with this structure it is possible to dispense with theseal and easing previously described inasmuch as the fluid within thetwo bellows employed for damping is contained within a restricted area.It is considered obvious that the passage 182, being of restricted area,provides a very effective means for controlling the movement of fluidbetween the two bellows 36 and 154 during acceleration. If desired,temperature responsive valve means may bev disposed upon the rod 159 forgoverning the amount of fluid transmitted between these two bellowsthrough the passage 182.

The structure shown in Fig. 10 of the drawings also differs from thatshown in Fig. 6 in that the two bimetallic strips 168 and 170 arereplaced by two strips 190 and 192 of different metals having difierenttemperature coefiicients of expansion, so that as these two strips areheated the same result obtained with the bimetallic strips 168 and 170are accomplished. The principle of using strips of different metalsconnecting the shaft 84 with a member movable along a line can also beapplied to the structure shown in Fig. 6 of the drawing and thestructure shown in Fig. 2. Normally, however, it is preferred to utilizebimetallic strips with these other consttuctions.

Those skilled in the art will realize from the aforegoing descriptionthat the accelerometer constructions described are comparativelyefiicient for the purpose intended and mark a substantial improvementover prior related units on the market today. They will further realizethat these accelerometer constructions may be termed air-damped,temperature compensated potentiometers. It is possible to retain certainof the advantages of the invention by omitting one or more of thevarious novel features herein set forth or by substituting otherconventional constructions for one or more of these features. This,however, is not preferred inasmuch as the accelerometers hereindescribed and the combination of parts set forth are exceedinglysatisfactory.

Those skilled in the art will unquestionably realize that many of thefeatures of this invention which, if desired, may be termedsub-combinations may be adapted to a number of different varieties ofrelated electrical devices. In all of such related units a firstelectrical means is moved with respect to a second electrical means inorder to vary an electrical value. It is considered obvious, because ofthis, that the instant invention is to be accorded comparatively widescope, and is capable of a number of distinct modifications notspecifically set forth in this present specification. Insofar as suchmodifications are within the scope of the art, and are setv forth in theappended claims, they are to be considered as part of the invention.

We claim:

1. An electrical instrument comprising a member supported for movementalong a substantially linear path, a rotatable shaft disposed at rightangles to said linear path of movement, an arm attached to said shaft,contact means on said arm, a resistance element wiped by said contactmeans, link means operatively connecting said member and said shaft,said link means including a lever arm attached at one end to said shaftand extending therefrom in a direction generally perpendicular to saidlinear path of movement, the other end of said lever arm being connectedto said member by means providing a connection movable lengthwise ofsaid lever arm, said link means being operable to vary the effectivelength of said lever arm responsive to changes of temperature, so as tocompensate for variations in the output of said instrument caused by thechange in temperature.

2. An electrical instrument as defined in claim 1 wherein said lever armcomprises a curved bimetallic strip operable to increase or decrease itseffective length responsive to temperature changes.

3. An electrical instrument as defined in claim 1 wherein said lever armcomprises: two oppositely bowed bimetallic strips, the extremities ofsaid strips being joined together, said other end of said lever armbeing movable in the direction to vary the effective length of the leverarm responsive to temperature changes.

4. An electrical instrument as defined in claim 1 wherein said lever armcomprises: curved bimetallic strips located on opposed sides of saidlinearly movable member, the outer ends of said bimetallic strips beingjoined to a pin extending generally parallel to said shaft, said. pinengaging slot means within said linearly movable member.

5. An electrical instrument as defined in claim 1 wherein said lever armcomprises: two curved bimetallic strips, the extremities of each of saidstrips being joined. together, each of said strips being of. differentcomposition, said two bimetallic strips of different composition be ingoperable to move said other end of said lever arm both in the direction,to lengthen or shorten the effective length thereof, and in thedirection generally parallel to the line of travel of said memberresponsive to changes in temperature, so as to produce a functionaltemperature compen: sating effect.

6. An electrical instrument as defined in claim 1 wherein said lever armcomprises a rod capable of ex'-- pending along its axis, so as to varythe length of said. link means.

7. An electrical instrument including: a can-like cas ing; a lid sealingsaid casing; a first bellows. mounting member positioned within saidcasing adjacent to the bottom thereof; a first bellows secured to saidfirst bellows mounting member; means defining a first orifice leadingfrom the interior of said first bellows into said casing; a secondbellows mounting member positioned within said casing adjacent to saidlid; a second bellows secured to said second bellows mounting member;means defining a second orifice leading from the interior of said secondbellows into said casing; a rod positioned between said first and saidsecond bellows, said rod being secured to said first and said secondbellows so as to be capable of movement during the expansion and.contraction of said first and said second bellows; a shaft rotatablymounted in said casing at one side of said rod between said first andsaid second bellows; an arm secured to said shaft; first electricalmeans attached to said arm; second electrical means mounted in saidcasing adjacent to said first electrical means; link means connectingsaid shaft and said arm, said link means in,- cluding means capable ofchanging length at. difierent 9 10 temperatures; and means for lockingsaid rod in a fixed 2,264,487 Smulski Dec. 2, 1941 position. 2,435,254Ramberg Feb. 3, 1948 2,484,165 Hathaway Oct. 11, 1949 References Citedin the file of this patent 2,702,186 Head et a1. Feb. 15, 1955 UNITEDSTATES PATENTS 5 FOREIGN PATENTS 2,067,803 Thearle July 12, 1937 642,850Great Britain Sept. 13, 1950 2,231,957 Shrader Feb. 18, 1941 693,958Great Britain July 8, 1953

